1. Filed of the invention
The present invention relates to a method of and a system for setting processing conditions of a laser processing system such as a laser marker which performs processing such as printing or marking including characters, symbols and graphics on work with a laser beam, a computer program for setting processing conditions for a laser processing system, a computer-readable recording medium or device on which laser processing conditions are recorded.
2. Description of Related Art
A laser processing system scans a given scan field of a subject surface of works (work surfaces) such as components and finished products with a laser beam to apply processing, such as printing and marking of characters, symbols and/or graphics, to the work surfaces. Referring to FIG. 1 for the purpose of providing a brief description of a configuration of a laser processing system by way of example, the laser processing system comprises a laser control unit 1, a laser output unit 2 and an input unit 3. Excitation light generated by a laser excitation device 6 of the laser control unit 1 excites a laser medium 8 of a laser oscillator 50 of the output unit 2. A laser beam L emanating from the laser medium 8 is expanded in beam diameter by a beam expander 53 and directed toward a scanning head 9. The scanning head 9 deflects the laser beam L so as to scan a work W in a given scan field, thereby processing, e.g., marking or printing, the work W.
There laser processing system is used to print symbols such as barcodes and two dimensional codes besides characters and numerals not only on plane work surfaces but on curved work surfaces. However, when reading such a print pattern on a curved work surface by an optical barcode reader, an optical 2D code reader or an image recognition equipment, a read rate of such an optical reader deteriorates due to deformation of the print pattern which occurs according to an occurrence of an angle of an optical axis of the optical reader with a normal to the work surface. This is because an image that the optical reader reads is an orthogonal projection of the print pattern thereto. Specifically, in the case of a barcode print that is printed on a columnar work surface W in circumferential direction as shown in FIG. 2, bars and spaces that the optical reader reads have distortion which becomes larger as the bars come father away from an optical axis of the optical reader. In consequence, narrow spaces and pitches of the narrow spaces between bars of the barcode become relatively smaller as the bars come farther away form an optical axis of the optical reader. If an angle of the optical axis of the optical reader with a normal to a work surface becomes large enough to be measurable, the optical reader encounters read errors. In the case where the angle of the optical axis of the optical reader with a normal to a work surface has an adverse effect on readability of the optical reader, it is essential to change a layout of a barcode on the columnar work surface so as thereby to make distortions of the barcode as small as possible. That is, it is necessary to print the barcode on the columnar work surface in a lengthwise direction as shown in FIG. 3. However, many objects or work surfaces impose constrains on printing areas, which is of a major problem in the laser processing system.